80% Seminar: Analysis of sub-synchronous control Interaction in wind power plants

The main objective of this research is to investigate and analyze the phenomena of sub-synchronous control interaction (SSCI) in doubly-fed induction generator (DFIG) based wind turbine. This is done by designing a mathematical model of the DFIG and performing an eigenvalue analysis on its linearized model. The eigenvalue analysis is performed to observe the contribution of the DFIG control parameters as well as the components of the electrical network in triggering the control interaction at sub-synchronous frequencies. The control parameters which play main role in making the modes of sub-synchronous frequencies stable or unstable are identified and analyzed. The theoretical findings of the analysis are also validated using the experimental setup of the DFIG system. The designing of a mitigation technique for SSCI is also a part of the project. A power oscillation damper (POD) is designed based on residue method. The proper installation of POD in DFIG control system shows that the oscillations caused by SSCI can be effectively mitigated.